Guide
Karat vs carat: gold purity vs diamond weight.
They sound the same and share a history, but they measure different things. A gold karat is purity: how many parts in 24 are gold. A diamond carat is weight: 200 milligrams.
Updated October 28, 2026 · Prices as of November 3, 2026, 4:45 p.m. Pacific
The difference
| Karat (K or kt) | Carat (ct) | |
|---|---|---|
| Used for | Gold | Diamonds and gemstones |
| Measures | Purity: parts of gold in 24 | Weight |
| Example | 14K = 14 parts in 24 = 58.3% gold | 1 ct = 200 milligrams |
| Top value | 24K, pure gold | None: stones can weigh many carats |
In the U.S., "karat" is the spelling for gold purity and "carat" for gem weight; the FTC's jewelry guides use them that way. In British English, "carat" is used for both, so a British ring might be "18 carat gold" with a "1 carat diamond."
Why they sound alike
Both words come from the same root: the Greek keration, the carob seed, used as a small weight in the ancient world. Gold's karat comes from a Roman gold coin that weighed 24 carob seeds; see why gold is measured in karats. The gem carat kept the meaning of a weight, varied from place to place for centuries, and was fixed internationally at exactly 200 milligrams in the early 1900s.
When you sell a ring
- The gold is paid by its weight and karat: a 14K band is worth its weight times 58.3% times the gold price.
- The diamond isn't gold, so a gold buyer doesn't pay for it. Its value depends on its carat weight, cut, color, and clarity, and is set by a jeweler or gem buyer.
- Remove valuable stones before selling the gold, or ask us about the piece. See gold rings.
We pay 94% of the gold value for karat gold: $69.16/g for 14K today.
Scrap prices are per gram of metal after melting, not per gram of what you send. Stones are removed, and dirt, glue, springs, and anything else that isn't gold or silver burn off or separate out, so the weight paid is usually less than your scale shows.
Sources
- 16 C.F.R. Part 23, FTC Guides for the Jewelry, Precious Metals, and Pewter Industries (§23.3 on karat gold; §23.12 on the carat, "equivalent to 200 milligrams").
- NIST, Special Publication 811 (1 metric carat = 200 mg).
- Merriam-Webster, carat and karat.
Gold guides: Why gold is measured in karats · Gold karat chart · Gold rings · Wedding bands · All guides
We pay top dollar for gold, at published rates set before you sell.
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